Hello. In November, I bougth a 3DS so I could download the Pokémon app before the most recent update. I also bougth a R4i3D (NEW), because I needed a new one, as I was going to give my DSi to my nephew, and this was the only flashcard on sale. Since then, I updated once, and my 3DS have the new one donwloaded, just waiting to be instaled. The question is:if I instal this update, will it do any damage to my 3DS sistem, like stopping the download of more Pokémon for the pokédex, or blocking the access to the internet, or even stopping me to, in the future, use some thing in the console? the r4 sometimes give some errors, so it could also make it worse?

About the flash cart, there's some bricking rumors going around. There's no way to tell if it will brick your system or not in future, but, up to this point, nobody had issues with a bricked 3DS.
Personally, I keep my Nintendo DS Lite for homebrew and stuff, and I keep flashcarts away from my 3DS.

Thanks for the info, now I already updated to 3.0-6, and its working fine, and now I'm using my old, stable purple R4iTT card again (got a second purple R4iTT to give to my nephew), but I heard something and wanted to be sure: if I use it on my 3DS while the wi-fi is on, can it be blocked (as in, the flashcard stops working)?.